I have a ISL in my rig. I had a similar problem when I filled up with B20 after not using bio-diesel for a while. Seems bio-diesel has more solvent and dissolves more of the crud at the bottom on your tank. After filling up, I was getting a miss/hesitation especially when climbing. As a temporary fix, I put some Diesel Kleen in and got home (1000 miles). Once home and replaced both fuel filters and no further problems.
Even though you've had service done recently, it's much cheaper to dump some Diesel Kleen in and replace those fuel filters as opposed to someone diagnosing your wiring harness.
Tom and Katharine
'07 Winnebago Tour 40TD, 400hp Cummins
'17 Winnebago View 24V, '02 R-Vision B+
RVing for 20 years & 200,000+ miles